Geography-altering machines such as bulldozers, wheel loaders, and other earth moving equipment, may alter a landscape of a worksite in accordance with a predetermined plan. The predetermined plan may specify certain dimensions of the worksite and the geography-altering machines may alter the landscape in accordance with the predetermined plan.
Each machine may have an on-board communications system, an on-board computer, and a memory including a database. The on-board communications system may send and/or receive data associated with the work being performed by the machine. The on-board computer may display information regarding the landscape of the worksite and work being performed by the particular machine. The memory, including the database, may be electronically coupled to the on-board computer. The on-board communications system may electronically communicate with a communication system at a remote location so that when the worksite is geographically altered by the machine, a composite model of the worksite located at the remote location may be updated.
The composite model typically represents a topography of the worksite as one or more machines alter the landscape of the worksite. Typically, in order for each machine to store and update the composite model, large amounts of data must be exchanged between the machines and the office. In addition, the data should be transmitted often so that the composite model at each machine is kept current. Thus, due to the large amount of data required for the composite model and the frequency such data is to be transmitted, the composite model is not available to the multiple machines in a near real-time manner. Therefore, when multiple machines are operating to alter the landscape of a section of land, for example, operators of the machines may not have an accurate depiction of their collective work. Rather, a viewable composite model available to each machine operator typically only reflects changes to the landscape made by that machine.
U.S. Pat. No. 5,646,844 to Gudat et al. discloses a system in which information regarding the composite model is made available to all machines operating on the worksite in a real-time basis. The machines may share a common, dynamically-updated database that stores updated terrain data or, alternatively, each machine may contain its own dynamically-updated database. Terrain data (or information) may include types of data associated with a worksite to determine a status of a project at the worksite. For example, terrain data may include elevation data, coverage data, compaction data, or material type. A terrain cell, associated with the terrain data, may also include an indication of time. The indication of time is used to determine if a received terrain cell is newer than current terrain data in the database. The database is updated only if the incoming data is newer.
Gudat et al. discloses calculating a position of the machines and alterations to the worksite by each machine based on raw Global Positioning System (GPS) positions received by a GPS sensor located on each machine. Raw GPS positions are coordinates transmitted from multiple GPS satellites, typically four (4) GPS satellites, that represent x, y, z positions and time (t). The raw GPS positions may be used by each machine's computer processor to determine specific terrain data associated with that machine and thus the work performed by that machine on the worksite. In order to calculate the terrain data, the machine takes into account particular characteristics of the machine, such as the type of machine (bulldozer, compactor, excavator, etc.), width and length of the implement (e.g. a blade), the distance of the GPS sensor to the implement or ground, and possibly other parameters inherent to the type of machine.
In the system of Gudat et al., raw GPS positions of one machine (e.g., a sending machine) are shared with other machines (e.g., receiving machines) on the worksite. The receiving machines use the received raw GPS positions of the sending machine to calculate specific terrain data associated with the sending machine and update a composite model with each of the receiving machines based on specific terrain data of the sending machine. In order to accomplish such updating, however, the receiving machines are required to store information concerning the particular characteristics of the sending machine (e.g., type of machine, width and of the blade, the distance of the GPS sensor of the sending machine to the ground, etc.). Thus, the receiving machines re-calculate the terrain data upon the initial receipt of the raw GPS positions. The process is repeated for all the machines at the worksite by continuously sending raw GPS positions of each machine to the other machines of the worksite. Such re-calculations are inefficient. Moreover, because each of the machines on a particular worksite are required to store the particular characteristics of all the other machines in order to compute the specific terrain data attributed to those machines, considerable processing time and effort is required to update the composite model at each machine. Further, the transmission of raw GPS positions may become voluminous because the raw GPS positions are sent regardless of whether any work on the worksite has been conducted by a particular machine. Accordingly, information may be transmitted unnecessarily between machines (i.e., raw GPS positions may be transmitted between machines even though no updating of the composite model is required).
Also, delays in processing the GPS data may introduce errors. For example, if processing occurs every five seconds, there may be deviations between the terrain data derived from raw GPS positions from a machine and the actual terrain data of the worksite.
The disclosed system is directed at overcoming one or more of the shortcomings in the existing technology.